Just in Case
by Lady of Lorule
Summary: Set before Avengers: Age of Ultron Bruce knows that the world needs to be protected from the Hulk. And he has an idea for how to save them. If he can just get Tony on board...


"I am not doing this!" Tony yelled, pacing around his lab as he tried desperately not to look at Bruce.

"Tony, come on, I need your help with this!" he said, following the billionaire. "I can't do this by myself. I need your mechanical knowledge."

"No, no, and no. I am not making some giant metal cage to trap you in!" he retorted hotly, throwing a wrench at a wall in frustration. "What makes you think I would help you with this insane idea? Because this is insane, even for the both of us!"

"No, it's not. Its practical. You just don't want to accept that," Bruce said calmly. "And you'd be trapping the other guy, not me. Tony, please. It's just a precaution, but it might save thousands, if not millions, of lives."

The billionaire froze, hands gripping the table almost hard enough to draw blood on the sharp edges. The doctor waited patiently across from him, hands spread in a pleading gesture. Tony didn't like Bruce's idea, didn't like it at all. But if it would give his friend some peace of mind, and put this ridiculous idea to rest, then Tony could play along. It would be costly, and the others probably wouldn't like it either, but it had to be done. Even if Bruce hadn't asked him to, he was sure the government would come knocking any day with the project.

"This just seems really extreme," Tony complained.

"Well, what in our lives isn't extreme? Please, Tony."

"It's unlikely that we'll ever even need to use this."

Bruce raised his eyebrows. "I don't find it unlikely at all, all things considered. And if you don't think we'll never be using it you should have no problem making it."

Tony snorted, raking a greasy hand through his hair. He'd been working on one of his vintage cars when Bruce had sprung his request on him. Not that he even seemed to notice. In fact, he probably didn't even notice. Grease had covered Tony for most of his life.

"Fine, I'll help," Tony said grumpily as Bruce smiled gratefully. "Though I want it to be noted that I am wholly against this. I am only reluctantly complying because I can tell you won't let this go if I don't. Did you catch that, F.R.I.D.A.Y.?"

"Message recorded, sir," the A.I. replied. He nodded in satisfaction.

"Thank you," Bruce said sincerely. Tony simply shrugged, and with a wave of his hand pulled up files on the Hulk. The holographic screens hovered over his work table.

It didn't look promising. Because of the Hulk's volatile nature, there weren't exact measurements on his size, height, weight, strength, and other rather important factors. But he did have estimates, and that was all he needed to start his work.

"Just so you know, it's highly likely that whatever I make won't be strong enough to actually contain...the other guy," Tony warned, using Bruce's preferred moniker for the Hulk. "We're not sure if we've seen his full potential yet."

"I know. I'd say overestimate on the strength factor whenever you can."

Tony pulled up some clips of the Hulk actually attacking things. He had even torn through Chitauri ships like they were made of paper. Ideally, he could use a large amount of vibranium to contain the Hulk, but Wakanda was incredibly stingy with their precious and versatile metal. Especially towards Stark Industries, since Howard had taken vibranium illegally and used it to make Captain America's shield, a weapon of war. Just another reason Tony had to hate his father.

"And just in case this fails…" Bruce said, eyes locked on a clip of the Hulk tearing through the Helicarrier. "Tony, I want you to make another suit. A new Iron Man suit strong enough to knock the other guy out."

He stared at the doctor in shock. "I don't even know if that's possible. Or advisable. Probably both. Won't he perceive me as _more_ of a threat if I'm in an enormous metal suit?"

"Possibly," he conceded as Tony choked. "In the event we actually need you to use this suit it will probably be too late to calm the other guy down anyways. Both of these are for last case scenario events."

Tony rubbed his temples. "What about the lullabies? I thought you and Natasha were making great progress with those."

Bruce fiddled with his glasses. "We are. But if I'm putting civilians in danger, we won't always be able to wait for Natasha to come. And right now the lullabies only work about half the time. We need a better insurance policy than that."

"I hate this," Tony complained, banishing the hologram.

"I really do appreciate this."

Silence fell. Tony didn't have anything to say that wasn't biting. Bruce seemed too relieved to really care. It was almost like a weight had been lifted from his shoulders. Tony's mind, however, wasn't eased at all.

"How long have you been thinking about this?" Tony asked softly.

Bruce sighed. "Ever since the experiment went wrong. I just never had the means to actually enact the plan until now."

Tony just swallowed and nodded. Time to get started.

The plans came together much too easily. Through long days and late nights, Bruce's vision was slowly realized. Tony did the actual construction, not trusting anyone else with the project. He built it and made a personalized A.I. for it, who he called Veronica. He hated to admit that creating the Hulkbuster armor was fun, a unique kind of challenge that always filled him with maniacal energy and unrelenting motivation.

It was a month after that first conversation that Tony walked into Bruce's lab to give him the news.

"There. All done. Veronica's in orbit, ready and waiting," he said, trying to keep the bitterness out of his voice. He couldn't believe he had created something so awful, something made to trap one of his best friends. It felt fundamentally wrong.

Bruce looked pleased. "Thank you."

The billionaire dropped onto a chair, rubbing a hand across his face roughly. "Well, what are friends for?"

After all, Veronica was just a precaution. Tony didn't actually think that they would ever need to call her for help. Months passed without needing her, though she was always in the back of his mind. The lullabies got more and more efficient. They might never have needed her, if not for that little witch.


End file.
